1. Field of the Invention
The present invention relates generally to communications systems. More specifically, but without limitation thereto, the present invention relates to a quantum optical communication system that provides secure communications.
2. Description of the Related Art
To provide security for transmitted information, traditional optical communications systems require that the information be encrypted during transmission. Encryption is the procedure used in cryptography to convert “plaintext” into “ciphertext” in order to prevent anyone except the intended recipient from reading that data. Put differently, one of cryptography's primary purposes is hiding the meaning of messages, not the existence of such messages.
There are many types of data encryption, and they are the basis of network security. Data encryption techniques can be used to increase the security in data exchange and transfer over a shared transmission channel. In its simplest form, data encryption uses a “key” based on a particular algorithm to change the sequence of a package of data that contains a piece of confidential information (“plaintext”) so that the data is enciphered or “scrambled” into a form that appears to have no correlation with the embedded confidential information (“ciphertext”). An unauthorized user, who does not have the knowledge of either the encryption method (i.e., the encryption algorithm) or the key based on the encryption method, cannot easily decode the information. An authorized user recovers the embedded information in the scrambled data by using the “key” that is constructed based on the encryption method. Therefore, even if the unauthorized user obtains the scrambled data, the knowledge of both of the encryption method and the particular key is needed to decrypt the confidential information embedded therein.
However, even if a message is encrypted, any eavesdropper who has access to the communications channel can still detect and record the ciphertext of the message. Once the ciphertext is recorded, the eavesdropper is free to apply whatever present (or future) techniques are available in order to obtain the plaintext message from the ciphertext.
Current encryption methods are subject to various threats. For example, if the “level” of encryption of a message is not high enough, then the plaintext of the message may be obtained from the ciphertext by “brute-force” computation using a super-computer. Also, current encryption methods rely heavily on the fact that it is difficult to find the prime factors of very large numbers. However, there is no mathematical proof that prevents the existence of a fast factoring algorithm. Therefore, it is possible that a fast algorithm to find the prime factors of very large numbers may be found in the future. This would compromise many modern encryption methods.
Therefore, it would be advantageous to provide an improved means of secure data transfer.